1. Field of the Invention
This present invention relates to manufacturing reseal and pull tab liners which are combined in a closure and which have a pull tab for removing, upon first use, a liner adhered to the container. These types of reseal liners are manufactured and placed in the interior of a closure which is either threadably attached to a container or is snap fitted on the container neck. The pull tab liner is adhered to the rim of the container mouth and is removed by the user upon first use of the container contents. There is also a gasket or reseal liner placed in the interior of the closure to properly seal the container after removal of the pull tab liner.
2. Discussion of the Prior Art
Pull tab reseal liners are fairly well known in the container and closure arts. Historically, these reseal liners are cut out of a web of material and inserted into the closure. A pull tab seal is then prepared, cut out and inserted into the closure which is then threadably screwed onto the container neck. There are many drawbacks however to the prior art manufacturing methods for generating reseal liners and pull tab liners which are adhered to the mouth or rim of a container. First and foremost, since the combined inserted liner is made of multiple layers of varying materials, multiple steps have historically been required for assembly and insertion of the pull tab liner and closure reseal liner into the closure. Additionally, these manufacturing problems have resulted in the layers of the sealing liner material being mis-aligned within the closure and possibly causing the pull tab to be improperly placed along the threads of the container lessening the accessibility of the pull tab for the user.
U.S. Pat. No. 4,754,890 to Ullman et al teaches a tamper evident safety seal which is formed from a sealing liner having an integral tab portion and having a tab being double folded for release of the pull tab liner. The sealing liner for the Ullman reference combines a layer of foil and foam causing the foil to be folded over one edge and then mated with the foam before punching out the liner into the closure. However, one drawback in the tamper evident safety seal taught therein is that the fold over portion of the liner results in a large section of wasted material as opposed to utilizing only a small pull tab, as is used in most removable pull tab and reseal liner combinations. Additionally, the large section of fold over liner material can prevent the closure from sealing properly on the neck of the container before the fold over seal liner is removed thereby impeding the closure from threading onto the container completely or preventing an adequate seal of the container.
There are additional methods of forming a pull tab reseal liner comprised of a first section of wax paperboard overlaid by a separate section of aluminum foil and plastic or seal material, the paperboard acting as the liner in the closure and the aluminum foil and other seal material acting as the pull tab seal liner on the container. These systems, however, such as is shown in U.S. Pat. No. 5,261,990 require the wax paperboard to be punched into the die containing the closure, and in a separate process the pull tab and liner material is separately formed and stamped into the closure for later bonding to the container rim after attachment of the closure on the container. The first layer of paperboard is glued into position against the top wall in the closure above the threads. The pull tab and liner material is then forcibly inserted and frictionally held into place by the threads until later bonding to the container. However, in this embodiment, accurate positioning of the liner material within the cap and of the pull tab is difficult because the separate layers are not combined and pressed into the closure concurrently causing positioning problems with the layers and other assembly difficulties.